/Engine/Source/Runtime/Slate/Public/Framework/Application/SlateApplication.h
Dismisses a menu and all its children. The menu is determined by looking for menus in the parent chain of the widget.
void DismissMenuByWidget ( const [TSharedRef](API\Runtime\Core\Templates\TSharedRef)< [SWidget](API\Runtime\SlateCore\Widgets\SWidget) > & InWidgetInMenu )